In an air damper device comprising a columnar rod member wherein a rod inner end is a piston portion, and a cylindrical cylinder member reciprocally storing the rod member, there is an air damper wherein a rod member includes a groove portion penetrating the rod member in a diameter direction thereof, and a pin member passing through the groove portion is provided on an open end side of the cylinder member so as to prevent falling off the rod member from the cylinder member (see Patent Document 1, FIG. 7, and FIG. 8).
In the air damper in the Patent Document 1, in the pin member, both ends thereof are pressed against a through-hole provided in the cylinder member and assembled with the cylinder member, and the pin member does not have a function more than preventing falling off of the rod member.